Malonyl-CoA decarboxylase from mammalian and microbial sources will be purified and regulatory role of this enzyme in lipid metabolism will be examined. Primary structure of the thioesterase segment of animal fatty acid synthetase will be determined. The thioesterase specific for intermediate chain fatty acids will be isolated from Euglena gracilis and characterized. The possible role of this enzyme in the synthesis of intermediate chain fatty acids in sebaceous glands will be examined. The mechanism of hydorcarbon synthesis in animals will be studied with labeled precursors and cell-free preparations.